Process for making cigarette paper and resulting paper



throughout the paper.

United States Patent signments, to Olin Mathieson Chemical Corporation,

a corporation of Virginia No Drawing. Filed Dec. 30, 1954, Ser. No. 478,925 Claims. (Cl. 162-139) This invention relates generally to the manufacture of paper and more particularly to a paper suitable for cigarette wrappers.

The paper used for cigarette wrappers is ordinarily composed of substantially pure cellulose or a mixture of cellulose and minor amounts of substances which control the burning and ashing characteristics of the paper. The combustion products of the cigarette Wrapper, of course, unite with the combustion products of the tobacco and are thus inhaled by the smoker. In research on the combustion products of cigarette paper, especially under unfavorable conditions, as when the paper has impeded access to air, it has been found that among the various combustion products of the cigarette wrapper 3,4-benzpyrene and other polynuclear substances such as anthracene, pyrene and the like are formed.

It is therefore an object of this invention to provide a means for reducing or substantially eliminating the production of 3,4-benzpyrene in the combustion of the cigarette paper wrapper. Another object of this invention is to reduce or eliminate all traces of 3,4-benzpyrene from the smoke of cigarette paper, especially when the paper is burned or incinerated under unfavorable conditions such as when it has limited access to air. Another object is to provide paper for cigarettes having improved smoking characteristics.

After numerous experiments, I have discovered that cigarette paper impregnated with compounds of manganese, iron, cobalt, or nickel, the 25th, 26th, 27th, and 28th elements in the periodic table of the elements, burns with greatly reduced or without any appreciable amount of 3,4- benzpyrene being detectable in the smoke. Any compound of manganese, iron, cobalt and nickel that can be incorporated substantially uniformly in the cigarette wrapper is suitable for the purpose, but in most instances it is preferred to use a water soluble compound of one of these elements. In most cases I prefer to use from about .06% to 1.25% of the impregnant calculated as the metallic element in the impregnating compound because, ordinarily, not more than about 1.25% of the metallic element based on the weight of the paper is required, but any amount greater than this quantity which does not deleteriously aifect the burning characteristics of the paper can be utilized. Any quantity of the impregnant is beneficial, but in order to insure a significant removal of the undesirable polycyclic hydrocarbon from the smoke at least .06% should be used.

The mechanism through which the impregnants work is obscure, as are the reasons for the formation of 3,4- benzpyrene and other polynuclear substances. It is essential, however, that the elements be intimately associated with the cellulose as it burns. For this reason the impregnant must be dispersed substantially uniformly It is believed, but not definitely established, that the compounds of iron, manganese, nickel and cobalt have a catalytic elfect on the oxidation of the cellulose and repress the formation of the traces of polycyclic hydrocarbons as the cellulose is burned. In any event, in order to achieve the objectives of the invention the impregnant must be present in the paper and cannot be placed in the tobacco instead.

The impregnant may be incorporated in the paper at any time during its formation so long as the proper precautions are taken to retain it in the finished product. If the compound utilized is water soluble I prefer to incorporate the impregnant in the paper sheet after it has been dried by wetting the paper with an aqueous solution of the compound of manganese, iron, cobalt or nickel and thereafter removing the moisture from the sheet. Such a procedure insures that the desired element will be present in the finished sheet. If the particular compound chosen is water insoluble it is advantageous to incorporate it in the sheet by adding the compound thereof to the pulp in the beater prior to its formation into a sheet.

In order further to clarify the invention, the following non-limiting examples are given of processes suitable for making paper in accordance with embodiments of my in vention:

Sheet paper formed from flax and precipitated chalk was impregnated with cobaltous chloride in the size press of the paper machine by wetting it with an aqueous solution of about parts by weight water and about 5 parts by weight cobaltous chloride (CoC1 6H O), thereafter passing the sheet between a pair of rolls to remove some of the solution and then drying. About parts of this solution was used to impregnate each 100 parts of paper.

sheet. The resulting dried paper had an analysis of about 26 parts calcium carbonate, 70 parts cellulose and 4 parts CoCl -6I-I O. The smoke obtained when this paper was burned contained substantially no 3,4-benzpyrene.

In a second example, a paper was formed in accordance with the same procedure as described above and was impregnated in the size press of the machine with an aqueous solution of nickel chloride. The aqueous solution used for this impregnation was prepared by dissolving about 5 parts by weight NiCl -6H O in about 95 parts waten of this solution were utilized to impregnate each 100' parts paper sheet. The resulting sheet contained about 4 percent by weight Fe (SO The amount of 3,4- benzpyrene found in the smoke obtained when this paper was burned was detectable but was substantially less than the amount obtained from conventional cigarette paper.

In a fourth example, a paper sheet formed as described above was impregnated with an aqueous solution of about 5 parts manganese chloride (MnCl -4H O) dissolved in about 95 parts water. About 100 parts by weight of this solution was utilized to impregnate 100 parts of paper sheet. As in the foregoing examples, the amount of 3,4- benzpyrene found in the smoke when this paper was burned was much less than the amount thereof found in the smoke of ordinary cigarette paper.

In another example, flax pulp was beaten in the conventional manner until ready for the paper machine. For every 100 pounds of pulp in the beater there was added 4.5 pounds of ferric sulphate. After the ferric sulphate had been thoroughly distributed a slight excess of caustic soda was used over that necessary to precipitate the iron as ferric hydroxide. After the caustic soda had been thoroughly distributed the beater was dumped in the usual way. To the pulp was added enough precipitated chalk to give a calcium carbonate content in the finished paper of 26 percent. The mixture was then run over the paper machine. The smoke from'the incinerated cigarette paper thus made showed a significant reduction in content of 3,4-benzpyrene. V

In still another example, the foregoing procedure was Patented July 17, 1962 The resultfollowed except that 5.9 pounds of cobaltous sulphate, CoSO -7H O, were used per 100 pounds of pulp. The sheet was found to contain 0.77 percent cobalt. The smoke from the incinerated cigarette paper made in this way showed complete absence of 3,4-benzpyrene.

As indicated hereinbefore, any compound of manganese, iron, cobalt or nickel or mixtures thereof can be utilized in accordance with my invention. The various compounds may be used singly or in combination and it has been found that when used in quantities in the amounts I have indicated desirable in the foregoing, the impregnants do not interfere with the mechanical properties of the paper, with the working properties of the paper during the manufacture of the cigarettes or with the smoking characteristics of the resulting cigarette. Indeed, the average smoker is unable to detect any difference in the smoking characteristics of the cigarette having the wrapper provided by this invention from that of a similar cigarette having the conventional unimpregnated cigarette wrapper.

Many embodiments have been described in detail in the foregoing for the purpose of illustration and it is to be understood that such detail is solely for the purpose of illustration and that those skilled in the art can make modifications therein without departing from the spirit and scope of my invention except insofar as the invention is limited by the appended claims.

What I claim is:

1. Cigarette paper consisting essentially of cellulose and a calcium carbonate filler and impregnated with about /z% to 6% manganese chloride calculated as 2. Cigarette paper consisting essentially of cellulose and a calcium carbonate filler and impregnated with about /2% to 6% ferric sulfate calculated as Fe (SO.,)

3. Cigarette paper consisting essentially of cellulose and a calcium carbonate filler and impregnated with about /2% to 6% cob-alt chloride calculated as COCIZ' 6H O 4. Cigarette paper consisting essentially of cellulose and a calcium carbonate filler and impregnated with about /2% to 6% nickel chloride calculated as NiCl -6H O.

5. Sheet paper suitable for wrapping tobacco and forming cigarettes consisting essentially of cellulose, calcium carbonate, and a compound of an element selected from the group consisting of manganese, iron, cobalt and nickel, said compound being present in minor proportion and substantially uniformly incorporated throughout said paper.

6. The process for dispersing a compound of the elements iron, nickel, cobalt and manganese in sheet paper consisting essentially of cellulose and a calcium carbonate filler, which comprises adding an aqueous solution of the compound to the pulp from which the sheet is formed, precipitating the metallic element as a water insoluble compound on the cellulosic fibers and thereafter dewatering the pulp and forming a sheet therefrom.

7. As a new article of manufacture, a cigarette wrapper consisting essentially of cellulose and a calcium carbonate filler having intermixed and intimately associated with the cellulosic fibers, from about 0.06% to about 1.25% calculated as the metallic element, of a compound of an element selected from the group consisting of manganese, iron, cobalt and nickel.

8. The process for making cigarette paper wrappers comprising substantially uniformly dispersing from about 0.06% to about 1.25%, calculated as the metallic element, of a compound of an element selected from the group consisting of manganese, iron, cobalt and nickel throughout the paper sheet; said sheet consisting essentially of cellulose and calcium carbonate.

9. Cigarette paper consisting essentially of cellulose and a calcium carbonate filler and impregnated with the hydroxide of cobalt.

10. Cigarette paper consisting essentially of cellulose and a calcium carbonate filler and impregnated with the hydroxide of nickel.

References Cited in the file of this patent UNITED STATES PATENTS 653,411 Crawford July 10, 1900 757,514 Thorns Apr. 19, 1904 1,334,752 Hagino Mar. 23, 1920 1,581,618 Sulzberger Apr. 20, 1926 1,761,069 'Booth June 3, 1930 2,003,690 Lewton June 4, 1935 2,547,948 Kornei Apr. 10, 1951 2,755,207 Frankenburg July 17, 1956 FOREIGN PATENTS 14,753 Great Britain Aug. 8, 1891 11,264 Great Britain June 8, 1895 443,766 Germany May 9, 1927 

5. SHEET PAPER SUITABLE FOR WRAPPING TOBACCO AND FORMING CIGARETTES CONSISTING ESSENTIALLY OF CELLULOSE, CALCIUM CARBONATE, AND A COMPOUND OF AN ELEMENT SELECTED FROM THE GROUP CONSISTING OF MANGANESE, IRON, COBALT AND NICKEL, SAID COMPOUND BEING PRESENT IN MINOR PROPORTION AND SUBSTANTIALLY UNIFORMLY INCORPORATED THROUGHOUT SAID PAPER. 